645501441523 has 4 divisors (see below), whose sum is σ = 645559758208. Its totient is φ = 645443124840.

The previous prime is 645501441511. The next prime is 645501441547. The reversal of 645501441523 is 325144105546.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 645501441523 - 2¹⁷ = 645501310451 is a prime.

It is a super-2 number, since 2×645501441523² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645501441503) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 29141736 + ... + 29163877.

It is an arithmetic number, because the mean of its divisors is an integer number (161389939552).

Almost surely, 2^645501441523 is an apocalyptic number.

645501441523 is a deficient number, since it is larger than the sum of its proper divisors (58316685).

645501441523 is a wasteful number, since it uses less digits than its factorization.

645501441523 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58316684.

The product of its (nonzero) digits is 288000, while the sum is 40.

The spelling of 645501441523 in words is "six hundred forty-five billion, five hundred one million, four hundred forty-one thousand, five hundred twenty-three".